Condensed Matter > Mesoscale and Nanoscale Physics

Title:
Self-sustained current oscillations in the kinetic theory of semiconductor superlattices

Abstract: We present the first numerical solutions of a kinetic theory description of
self-sustained current oscillations in n-doped semiconductor superlattices. The
governing equation is a single-miniband Boltzmann-Poisson transport equation
with a BGK (Bhatnagar-Gross-Krook) collision term. Appropriate boundary
conditions for the distribution function describe electron injection in the
contact regions. These conditions seamlessly become Ohm's law at the injecting
contact and the zero charge boundary condition at the receiving contact when
integrated over the wave vector. The time-dependent model is numerically solved
for the distribution function by using the deterministic Weighted Particle
Method. Numerical simulations are used to ascertain the convergence of the
method. The numerical results confirm the validity of the Chapman-Enskog
perturbation method used previously to derive generalized drift-diffusion
equations for high electric fields because they agree very well with numerical
solutions thereof.